The installation and uninstallation of the current wall lamp, especially the street lamp, the mining lamp, the stage light, and etc., are extremely inconvenient. The general wall lamp is equipped with a power adapter. In order to protect the power adapter, the power adapter is usually installed in a closed space, in most cases, in the lamp cover. In that way, the installation and uninstallation of the wall lamp is very inconvenient. After the wall lamp is fixed to the wall, it needs to connect the power supply. The old installation method is to connect the power supply first, and then fix the wall lamp to the wall. This method is extremely inconvenient. The wall lamp may easily slip down during the installation which may cause damage. Further, it is hard to confirm whether the connected power supply wire falls off after the wall lamp slips down. This may causes security risks. Therefore, there is a demand for a wall lamp that is safe and easy to install and uninstall.